The Chain Gang (1930), Mickey was a prisoner (wrongly convicted, no doubt). When he escaped, Pluto, making his first appearance in cartoons, was one of the dogs that tried to track him down.

In that cartoon, the dog character has no name. In his second appearance, The Picnic (1930), he is called Rover, and cast as Minnie's dog. Only in the third, The Moose Hunt (1931) does he assume his now-familiar position as Mickey's faithful pooch, Pluto (probably named after the planet, which was discovered in 1930, about the time The Moose Hunt was in production).

Pluto was by then one of the Disney regulars, and on his way up. In 1936, he received his first star billing, in the Silly SymphonyMother Pluto; and from there, he went on to star in his own series of cartoons. Altogether, he appeared in over 100 theatrically-released shorts — sometimes as the star, but more often as Mickey's dog.

In comics, as in cartoons, Pluto was mostly Mickey's supporting character — but there, too, he had occasional bouts of stardom. He had his own Sunday newspaper comic strip during the late 1930s. In 1942, he headlined his first comic book — Dell'sLarge Feature Comic #7 (which, incidentally, contained the first comic book work of Carl Barks, creator of Uncle Scrooge). Between 1952 and 1962, he starred in ten issues of Dell's Four Color Comics, several of which were reprinted during the 1970s in Walt Disney Showcase. He also made regular appearances in the back pages of Walt Disney's Comics and Stories during the 1940s and '50s.

Today, Pluto can be seen in comic books in various parts of the world, in cartoons rerun endlessly on The Disney Channel, and even in new animation, broadcast in the "Mickey Mouse Works" segment of Disney's One Saturday Morning, or its successor show, House of Mouse. Even now, he is only occasionally a star — mostly, he appears in the role of Mickey Mouse's dog.